Financial markets appear to have latched on to the bookmakers rather than polls, and the pound strengthened ahead of voting in the UK.
Mark Johnson, senior foreign exchange and derivatives dealer at OMF, said if the "remain" camp wins and the New Zealand dollar rallies, the gains could be amplified by traders who had bet on a Brexit and a weaker Kiwi being forced to buy back their positions.
If the Brexit campaign wins, "there's going to be a risk-off tone" in financial markets, he said.